Aminodiglycol (ADG) [=2-(2-aminoethoxy)ethanol=2,2′-aminoethoxyethanol, formula
and morpholine are used, inter alia, as solvents, stabilizers, for the synthesis of chelating agents, synthetic resins, drugs, inhibitors and surface-active substances. N-Ethylmorpholine (E-MO) is used, inter alia, as catalyst for the production of polyurethane foams.
Numerous methods of preparing ADG and morpholine are described in the literature.
Ullmann's Encyclopedia of Industrial Chemistry, 6th Edition, 2000 electronic release, Wiley-VCH Verlag, Rubrik ‘cyclic amines’ in the chapter ‘aliphatic amines’, describes the synthesis of ADG and MO by amination of DEG under hydrogen pressure and in the presence of a cobalt or nickel catalyst (citations: EP-A-696 572 (BASF AG), DE-A-1 049 864) or other catalysts (citations: DE-A-3 002 342, DE-A-3 125 662 (BASF AG), U.S. Pat. No. 3,155,657).
The earlier German patent application No. 102005047458.6 of Sep. 30, 2005 and the earlier European (subsequent) patent application No. 06101339.7 of Feb. 6, 2006 (BASF AG) relate to a process for preparing ADG and morpholine by reaction of DEG with ammonia in the presence of a specific copper, nickel and cobalt heterogeneous catalyst and also in general terms the work-up by multistage distillation.
Two parallel European patent applications having the same filing date (both BASF AG) relate to processes for the continuous fractional distillation of mixtures comprising morpholine (MO), monoaminodiglycol (ADG), ammonia and water obtained by reaction of diethylene glycol (DEG) with ammonia.
A parallel European patent application having the same filing date (BASF AG) relates to a process for preparing electronics-grade ADG.
The synthesis of morpholine and monoaminodiglycol is notable for the formation of many secondary components. Unreacted starting materials, products of value and the by-products are separated off by distillation, which leads to a considerable outlay in terms of apparatus and energy.